The practice of agglomerating finely-divided granular tetrafluoroethylene polymer particles to increase their flowability while retaining their moldability properties is known. One method of agglomerating the finely-divided granular tetrafluoroethylene polymer particles is to agitate them in a two phase liquid medium of water containing an organic liquid that is capable of wetting the particles and which is soluble in water to at most only about 15% by weight at the operating temperature. The solubility requirement means that the organic liquid is substantially immiscible in water.
It is also known that blends of the finely-divided polymer particles and particulate filler materials can be agitated and agglomerated in the same manner. However, if the filler material is metallic, filler is lost to the aqueous phase during the agglomeration process.
Such loss is undesirable for several reasons. For example, quality standards are difficult to maintain since the loss can vary from batch to batch. Moreover, it is costly to recover lost filler from the aqueous phase and costly to be forced to use more filler than necessary in the initial blend in order to get approximately the right amount in the agglomerated product. In addition, the loss is visibly noticeable in the final molded product because of loss of filler from the surface of each agglomerated particle.